The present invention relates to variable pitch aircraft propellers of the general type disclosed in U.S. Pat. No. 3,380,535, No. 3,575,529 and No. 4,097,189 assigned to the assignee of the present invention. These propellers usually incorporate a control mechanism for changing the pitch of the propeller blades between a feather position and a reverse position through high and low pitch positions. More specifically, the variable pitch aircraft propeller includes a hydraulic actuating cylinder assembly which rotates with the hub of the propeller and receives hydraulic fluid from a governor unit driven by the aircraft engine. The governor unit preferably incorporates a positive displacement hydraulic pump which supplies hydraulic fluid through a governor control valve actuated by flyball weights responsive to the speed of the engine shaft. The governor control valve operates to maintain the engine speed substantially constant by precisely controlling the pitch of the propeller blades, but can be manually adjusted to change the blade pitch during flight.
As disclosed in above-mentioned U.S. Pat. No. 4,097,189, it is desirable for the aircraft propeller assembly to incorporate stops which limit or precisely establish the pitch of the blades at the feather position and also at the reverse position. As illustrated in this patent, the blade pitch reverse position is determined by an adjustable stop or plug member threadably connected to the forward end of the hydraulic cylinder. The stop for the feather position is provided by an internal shoulder within a tubular sleeve surrounding an annular stop member secured to the forward end of the piston rod. While the stop for the reverse position may be adjusted on the propeller disclosed in U.S. Pat. No. 4,097,189 after the spinner or cover has been removed, the stop for the feather position of the propeller blades may not be easily changed or adjusted without disassembly of the hydraulic cylinder from the propeller hub.